Ion thrusters used as propulsion for spacecraft generate thrust, and thus driving power, in that a fuel gas, such as, for example, xenon, is first ionized, and the gas particles are then accelerated in an electric field. In a neutralizer, the accelerated gas particles are electrically neutralized and finally ejected in the form of a jet at a speed of from 10 to 130 km/s. A gas inlet, via which the fuel gas, which flows through a fuel gas line connected to a fuel gas tank, is fed into the ion thruster, must ensure a defined inflow of the fuel gas into the thruster in order to allow the fuel gas to be distributed evenly in the thruster. Furthermore, the gas inlet must generate a defined flow resistance in order to ensure that plasma generated in the thruster does not flash over into the fuel gas line. This flow resistance should also remain as constant as possible in the case of a large number of thermal cycles to which the gas inlet is subjected in the course of its operating life.
Gas inlets currently fitted in ion thrusters comprise a plurality of components which are mounted in several steps. In a first step, a gas inlet housing is manufactured, into which a first sintered filter is then introduced. Glass beads or quartz sand particles having a diameter of less than 0.2 mm are then introduced into the gas inlet housing and compacted by a vibrating plate. The glass beads or quartz sand particles serve to establish the desired flow resistance of the gas inlet. A second sintered filter is then introduced. The sintered filters prevent the glass beads or quartz glass particles from falling out of the gas inlet housing. Finally, a cover is soldered to the gas inlet housing. The cover is provided with a gas inlet opening via which the fuel gas is fed into the gas inlet housing filled with glass beads or quartz sand particles.